Power Mac G3

[Redsward]

Hi all ,
I came into a couple of ‘ not working. For parts ‘ power mac G3’s (blue and white. )

Any suggestions on resources I can read to get to grips with issues .

I’m comfortable with component level repair, just not sure where to start with these!

 

[Kai Robinson]

Well, we have a pretty good resource section here, but also, just ask questions here!

We also have a very active discord server that can help.

Might be worth posting what you have, along with pictures as a starting point

 

[3lectr1c]

Most common issues with these are PSU and analog board related. The flyback transformer is a common failure in all revisions as far as I know, and bad caps on both boards are known to happen as well.

 

[Kai Robinson]

Most common issues with these are PSU and analog board related. The flyback transformer is a common failure in all revisions as far as I know, and bad caps on both boards are known to happen as well.

In a B&W G3?

 

[3lectr1c]

Skimmed the thread and wrote about iMac G3 faults...
Blue and white G3s are pretty bullet proof hardware wise - check the PSU for proper output voltage, then can't offer many ideas beyond that.

 

[flag4]

I have one of those sitting in the attic, the power mac, not the imac . .

From my limited experience, it's the usual suspects . . PSU and leaky caps.
If it has an airport card, they usually crap out too.

 

[3lectr1c]

airport cards are dying now? The B7W didn't support them either way.
The B&W G3 has all solid capacitors on the logic board, the beige one's don't.

 

[flag4]

I just checked my spare G4 boards, they have electrolytic caps. I could go check the G3 in the attic but I'm too lazy right now!

 

[3lectr1c]

Yep, the G4 boards have 'em. At some point I'll recap my sawtooth.

 

[Certificate of Excellence]

Before anything I would plug em in and see if a cuda reset will bring them back to life. My B&W on occasion has shown absolutely no life after fiddling with its bits - that behavior included non-functioning power button. It presents like a completely dead box/psu, so if you dont know, its easy to assume the box is dead. Anyhow, reset the CUDA and the machine comes back to life, so give that a try. Here’s a pic of a rev2 logicboard for @flag4 .

The cuda is behind the cpu heatsink and will be the button on the left. The button on the right is the power button. The difference between Rev 1 & 2 logicboards is found in the corner of the lobos CMD chip which is hidden under the PCI slots. Rev1 is PCI646U2 and Rev2 is 646U2-402.

 

[Redsward]

I just checked my spare G4 boards, they have electrolytic caps. I could go check the G3 in the attic but I'm too lazy right now!